The cast-list for Michael Winterbottom's new film A Cock and Bull Story - inspired by the experimental comic novel Tristram Shandy - reads like the guest list of last year's British Comedy awards. Steve Coogan, Rob Brydon, David Walliams, Dylan Moran, Ashley Jensen, Ronni Ancona, Stephen Fry and Mark Williams are all there; you half expect Jonathan Ross to stumble on screen to interrupt the proceedings with a couple of bawdy one-liners. And this isn't the first time Winterbottom has filled his cast with the cream of British comedy - 24 Hour Party People included performances from the likes of Coogan, Brydon, John Thomson, Ralf Little, Dave Gorman, Simon Pegg and Peter Kay. In short, a very funny bunch of people.

These days British cinema seems to be awash with terrestrial comedy talent, with varying results. Shaun of the Dead sprang from the creative forces behind Spaced and was a massive hit at the box office, taking more than £6m in the UK alone; The Hitchhiker's Guide to the Galaxy, featuring Tim-from-The-Office, was a glitzy big-budget affair and put a respectable number of bums on seats; while Sex Lives of the Potato Men (with Johnny Vegas, Mackenzie Crook, Mark Gatiss and Lucy Davis), almost universally panned by critics, was still far from a commercial flop.

Is hiring such recognisable faces just a low-budget attempt at a box-office safety net, or is it a bold move that's revitalising the British film industry? Andrew Eaton, producer of both A Cock and Bull Story and 24 Hour Party People, says that he and Winterbottom never set out to write a shopping list of potential TV talent. "It wasn't a conscious decision to sign up so many British comedians, the casting for Tristram Shandy just grew out of 24 Hour Party People and was focused around Steve Coogan's relationship with Rob Brydon. There were people Steve wanted to get involved, and Michael likes to work in a semi-improvisational way, so it just made sense to hire the cast we did."

Are these recent films isolated cases, or has there been a positive shift towards hiring comedians as leads in movies? "I really think it reflects a wider trend," says Eaton. "There's a lot more freedom to experiment on television, and this generation of comedians is so bold - they bring this confidence to the movies they make. Just look at the people behind Shaun of the Dead. They had some really clever ideas that worked brilliantly. They've come straight from television but are more adventurous than a lot of the people already making films. TV's much more rock'n'roll in that sense, they're driven by ideas rather than what middle America might think. It's a much more sophisticated attitude."

Condensing so much comedic talent into one picture has another positive side effect - they drive each other to excel. "The comedians are all quite competitive with each other. After finishing filming for the day, we'd go to the pub and you'd have Steve, Rob, Dylan and David Walliams all doing impressions of each other and competing to tell the funniest jokes. It was a joy to witness - people on the next table were reduced to tears it was so funny."

It might look like a sudden mass exodus from small screen to big, but it's nothing new for a television star to find success in films - Clint Eastwood was a household name in the TV series Rawhide long before he appeared in A Fistful of Dollars back in 1964, while John Travolta, Michael J Fox and Tom Hanks were established TV stars before they hit the multiplexes. But while there are obvious reasons why movie-makers would want to use familiar faces to draw in the crowds, these days it backfires just as often. It's been a Hollywood mantra for many years that audiences are reluctant to pay to see actors they're used to watching for free: witness the difficulty of the Friends cast trying to score at the cinema.

Of course, British cinema is littered with more TV spin-off casualties than most. Amid the detritus of the disastrous recession of the 1970s, companies such as Hammer, EMI and Associated London saw the box office takings of On the Buses in particular (the biggest commercial success of 1971) as a green light to raid the best, and occasionally worst, of the decade's TV for the big screen. Thirty spin-offs were produced between 1968 and 1980, including Dad's Army (1971), Steptoe and Son (1972), The Likely Lads (1976), Are You Being Served? (1977), and Porridge (1979), with the awful George and Mildred (1980) sounding the death knell for the trend by the end of the decade. Rowan Atkinson's Bean, a shrewdly Americanised version of his amiable British comedy, marked the return of the sitcom spin-off in 1997, and was a worldwide hit. This was followed by an assortment of flops and moderate successes, including Rik Mayall and Adrian Edmondson's Guest House Paradiso (1999), Harry Enfield's Kevin and Perry Go Large (2000), and more recently, Ali G Indahouse (2002) and The League of Gentlemen's Apocalypse (2005).

So is it a help or hindrance to be a familiar TV face before your movie appearance? Potentially both, says Wendy Brazington, casting director of A Cock and Bull Story. "Alan Partridge hadn't really caught on in the US by the time 24 Hour Party People came out over there and I think that helped Steve [Coogan]. Everyone was quite surprised at the amazing performance he gave and there was none of the snobbery you got over here of critics comparing Tony Wilson to Partridge.

"But at the same time, casting a number of well-known comedians can act like a signal for your audience - they come with a lot of funny baggage, which can be actively helpful if you're setting out to make people laugh. David Walliams is in the film [A Cock and Bull Story] for just a moment but brought to it something completely original that no one else could have done. Great comics set the bar that little bit higher for the rest of the cast."

Not everyone's so upbeat about comedians making the leap into cinema. British comedy's golden boy Ricky Gervais - conspicuous by his absence from the roll call of movie converts - recently bemoaned: "After the second episode of The Office I was offered the lead role in a film. I hate it when a British comedian becomes popular and the first thing they do is appear in four films and they're all terrible, lottery-funded, tacky shit."

His comment is significant, not least because his former fellow cast members - Martin Freeman, Lucy Davis and Mackenzie Crook - are among the vanguard of the drive towards film comedy. It wouldn't take long to concoct a version of Six Degrees of Separation where every recent British comedy flick is linked back to somebody in The Office.

We have already witnessed the media backlash. The tasteless Sex Lives of the Potato Men became tabloid fodder when it emerged that almost £1m of its funding had been granted by the UK Film Council. "Fury as Lottery money funds vile sex film" screamed the Daily Mail's front page, while the Times was prompted to ask "Is this the worst film ever made?" (Director Andy Humphries responded by arguing that the movie was made for "real cinema-goers ... not for middle-aged, middle-class film critics".)

Where successful TV comedians occasionally go wrong on film, says Eaton, is in their attitude to the switch: "Sometimes they feel as if they have to change [for cinema], so we end up saying to them, 'Just do the same.' I didn't think the League of Gentlemen film was as bold as the original programme, for example, and it suffered for that."

Artists have often come together in groups, so could we be witnessing the beginnings of a new creative movement? A collaborative web of ambitious, energetic associations and networks that began in television, now working together on film - The Office, Spaced, Little Britain, Black Books; jumbled around and then carefully reassembled by confident old hands like Coogan and Brydon. Fresh and genuinely funny, they've wiped any fond collective memories of a fusty pre-Office old guard; Harry Enfield, Lenny Henry, Rik Mayall, Victoria Wood - suddenly they feel as dated as Russ Abbot.

And where are the comic actors graduating from the nation's theatres to take their place in the limelight? Yet to materialise. So until then, this merry band of innovators will fill the void exploring galaxies, fighting zombies, making mistakes perhaps, but always pushing things forward.